Acoustic apparatus



M. WElL ACOUSTIC APPARATUS Dec. 25, 1928. 7 1,696,784

Original Filed y 20. 1924 3 Sheets-Sheet 1 g ,1 g 44 34, 44 ZQ J Z? 14 li A as INVENTOR' Marz'mz/z'an iI Pz/ fi vvz/M I M ATTORNEYS M. WEILACOUSTIC APPARATUS Original il y 20, 1924 s Sheets-Sheet 3 Dec. 25,1928. A 1,696,784

ATTORNEYS Patented Dec. 25, 1928.

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MAXIMILIAN'WEIL, or NEW YORK, 1v. Y.

ACOUSTIC APPARATUS.

Application filed May 20, 1924, Serial No. 714,574. Renewed November 12,1928.

My present invention relates to sound reproducers and more especially toamplifying sound reproducers, and has a preferred application tophonographs in which the usual horn or amplifier serves also. as thehorn or amplifier of a radio or telephone receiver.

It is among the objects of the invention to provide a combined apparatuswhich can be used at will, either as a phonograph or as a radio loudspeaker, without, however, 1nvolving any change or mutilation of theusual approved phonograph sound box, tone arm or amplifier, which avoidsany extra drag or wear on the phonograph record even though a telephonereceiver element much heavier than the usual sound box is employed, andin which the sound vibrations emanating from the receiver diaphragm areefiiciently amplified without loss by leakage, from near the throat ofthe amplifier.

Another object is to provide a construction of the type mentioned inwhich the volume of sound emitted from the amplifier horn in radiooperation, can be delicately varied or adjusted at will, withoutmanipulation of the electric control elements of the receiving set andwithout the loss in efficiency due to leak with respect to thephonograph tone arm. v

Another object is to provide atone modifier for a simple phonograph, orfor one combined with radio appurtenances, which in all settings thereofwill provide a continuous conduit for sound without sharp valve elementsprojecting across the sound passage that might impair the effectivenessof the production.

Another object is to provide a construction of the type mentioned devoidof arrangements or elements that might develop looseness or rattle,which may be incurred, for instance, in constructions embodying flapcontrol valves or involving the substitution of a radio receiver for thesound box in changing from phonograph to radio operation and vice versa.

Another object is to provide a unit or assembly simple, rugged andcompact, which willenhance the attractiveness of the phonograph andwhich can be easily applied, without the exercise of skill tophonographs of the type now in use, in order to accomplish the variousobjects previously noted.

In the preferred embodiment ofthe invens tion, the sound vibrationswhether from the phonograph sound box or from the telephone receiver orother telephonic speaker are admitted into the small end of theamplifying horn, so that the full length of the amplifying horn isincluded in the acoustic circuit for both phonographic and telephonicreproduction.

In a preferred embodiment, I provide a conduit which I call the radioconduit, preferably fixed with respect to the moto-rboard. mounting atelephone receiver element at its smaller end and flaring-to mergeflviththe sine. l end of the amplifier. Means is provided to prevent, duringradio operation, any communication between the radio conduit and theconduit that connects the sound box with the small end of the amplifier.For this purpose, I provide a valve, which in one setting shuts on thetone arm with respect to the amplifier throat, while affording a directcommunication from the telephone receiver to said throat, and in anotherposition affords communication between the tone arm and the amplifierthroat, while preferably closing oil the conduit leading from the radioreceiver. A rotary valve is preferred and more especially one which hasintermediate settings, so that it performs in addition to the functionsnoted, that of a tone modifier by which the volume 01 sound emitted fromthe horn can be regulated, either in phonograph or in radio operation,but preferably in both modes or" use.

The radio conduit is preferably embodied in a casting, the valveconstituting an element in the connection from said conduit to theamplifier throat, said valve also controlling a passage oi more orlossuniform crosssection, which I call the phonograph conduit, and whichconnects the mouth of the tone arm with the throat of the amplifier. Inthe preferred detailed construction, a unitary casting is provided whichmay be rectangular in external form, is secured to the motorboard andincludes both the radio and the phonograph conduits, cast thereinto, theformer preferably of rams-horn shape to provide conside able length in asmall length of casting, the latter relatively straight. lhe twoconduits extend preferably either diametrically opposite, or at someother angle relative to each other, and provide a valve casing at theirjunction in which is disposed the rotary control valve, the latteroperable by an exposed knob.

In the accompanying drawings,

F igL 1 is a. fragmentary top plan view of a phonograph embodying myinvention,

Fig. 2 is an enlarged view. in transverse section taken along the line22 of Fig. 1,

Fig. 3 is a view in longitudinal section taken along the line 33 of Fig.2.

Fig. 4 is a fragmentary view illustrating the controlling valve moved toits other extremeposition,

Fig. 5 is a plan view of the handle and dial for the. controlling valve,

Fig. 6 is a sectional view taken along the line 6-6 of Fig. 1,

Fig. 7 is a view similar to Fig. 1 showing the selector unit above themotorboard, and

Fig. 8 is a sectional view of one of many possible modifications.

The phonograph 10 shown of conventional construction includes amotorboard 11, above which is the usual-turntable 12 (Fig. 1) thatcarries the disk record 13, and is rotated by motor. (not shown). Inapplying my invention to a machine of this general character, themotorboard isformed with a cutaway portion or opening 1 1 for the acconrmo-dation of a casting 15, formed with a peripheral flange 16 seating onthe edges of the opening 1 1 and held in place by screws or similarsecuring devices 17, passed through lugs 18 at the ends of the flange.The exact shape of the casting is, of course, subject to considerablevariation, but for purposes of convenience in assembly andattractiveness in appearance, I prefer to make the body of this castingof generally rectangular shape fitting Within a rectangular opening 14int-he motorboa-rd. Aluminum is suitable for the casting, but variousother materials may be substituted.

Thetl'iroat 19 of the usual amplifier or horn is provided with anexternal flange 20 (Fig. appro iiriately secured to the lower end of acontrol valve housing 91, integral with and disposed aymroximatelycentrally of the casting. Rotatably mounted in the housing 21 is a valve22 operable to selectively place the amplifier 19 in communication witheither of a pair of conduits or pa. sage-ways 23 and 24. in the castingat opposite sides of the valve. The passage-way 2 1 is relatively wideand may be of substantially the same cross-sectional area. throughoutits length, although even along this short length, a slight taper isdesirable, and when the valve is set accordingly, connects the amplifier19 with the large end of the tone arm 25 of the phonograph. The tonearm, which may be ofenti'rely conventional construct-ion, carties thesound box Band is swiveled in a socket member 26 at the open end of thepassage 2 l which thus forms a continuation of the sound wave channel inthe tone arm. The tone arm 18 secured against accidental removal fromthe socket 2G by a stud 27 carried at the upper end of'a curved arm 28communicates with the face of the casing 1 18 provides a mounting for aradio repro; ducer of any desired type, such for instance, as thetelephone receiver 31. Preferably the receiver is formed with adepending socket member 32, encircling the projecting upper end of thebushing 30 andsecnredthereto by set screw 33. If it is desired to mountthe telephone in concealed rather than in exposed position, it may besecured to a boss 3% integral with the casting and communic-at in g wi lh the neck of the passage-way (Fig. 6). This boss or nipple isordinarilyclosed by a plug and the position of the plug 35 and bushing30 may be reversed when it is desired to attach the telephone in. aconcealed position within the motor casting.

As seen most clearly in Figs. 3 and 4, the rotary valve member is formedwith an opening or cut-away part 36 adapted for registration with therespective passages 23, 2 1 and is formed with an external groove 37receiving a set screw 38 projecting through the valve casing, engagingwith the ends of the groove to act as a stop and limit the turningmovement of the valve in each direction.

The conduit connecting the telephone receiver to the amplifier throatshould diverge and preferably be relatively long, so that the wave frontcan gradually increase frpm the relatively small receiver opening to themuch larger amplifier throat. On the other hand, the conduit 24connecting the mouth of the standard tone arm to the throat of theamplitier, which elements are of about the same diameter, is preferablyrelatively short, since this conduit acts as a connector with little orno amplification. For neatuess of construction, it is preferred toprovide the valve and knob near the center of the rectangularcasting andthe telephone receiver and tone arm at equal distances therefrom towardthe opposite sides thereof. Accordingly, to provide the long passage forthe radio conduit, the latter is made of reversely curved, generallyramsdiorn shape, while the former is relatively straight.

In the extreme positions of the valve, it is desirable that the latterprovide an effective opening as best shown in Figs. 3 and 1 with respectto the conduit of substantially the full'diameter of said conduit, yetin each This stud engages a fiat- IUU ofthese extreme positions, theeffective conduit is to he completely closedjoff fromthe other conduit.If the two conduits have equal. diameters, which is vpreferably the caseat the point of discharge to the amplifier andwere to merge in directalignment with each other,,it is apparent that the latter object couldbe attained, if at all, with diificulty where the diameter of the valveis kept at a minimum. By my arrangement, the rams-horn conduitcommunicates with the valve casing at an obtuse angle illustratively ofabout 1.35 degrees with respect to the con duit 24, the stop screw 38registering with peripheral groove 37 about the valve, limiting the,rotation of the valve through a corresponding obtuse angle, so thatefiective lengths of arc of the valve provide the closurebetween the twoconduits both in the position shown in Fig. 3 and in that shown in Fig.4, the effective length of closing arc of the valve at the front beingconsiderably more than 90 degrees and at the back being about degrees,in the specific embodiment shown. In all intermediate settings of thevalve, the communication between the radio conduit 25 and the phonographconduit 24 is effectively prevented, while either of these conduitsalone is in communication with the amplifier. VI hen the valve is in aposition midway between the extremes shown in Figs. 5 and 4, itcompletely shuts off ways to the amplifier.

For supporting and rotatlng the valve, I

both passageprovide a valve stem 40 extended through the top of thecasing 21 and suitably connected to a boss or lug 41 integral with thevalve.

The inner end of the valve stem may be burred at 42 to insure firmengagement with the valve, or the valve and stem may be rigidlyconnected together in any other convenient or conventional manner. Theend of the valve stem which projects beyond the housing 21 is securedwithin a tubular sleeve 43 rising from a circular plate 44. A set screw45 may be used to make this connection. The sleeve 43 is, in turn,rigidly fixed to a manually operable knob 46 which is used in rotatingthe, valve.

The manner of attaching the knob to the sleeve is not important but Ifind it convenient to form the knob with an integral depending socketportion 47 within which the roughened exterior of the sleeve 43 engages.The connection between the sleeve 43 and the socket 47 may be either aforce fit or molded connection. Both the knob 46 and the socket 47 areslotted at 48 to accommodate and provide ready access to the set screw45.

In order that the position of the valve 22 may be visibly indicated atall times, I pro' vide astationary dial member 49 associated with afinger 50 (Fig. 5) the latter rigid with the valve. Preferably thestationary dial member is fitted within a depression 51 on the top ofthe housing 21 and secured theretoby screws or similar devices 52.

To enhance the attractive appearance of the device and to facilitateoperation of the same, I prefer to cant or incline the valve housing 21.to approximately the angle shown in Fig. 2. Valve 22, isthus disposed atan angle to the vertical plane of the casting 15 and the upper outersurface of the housing 22 together with the dial and knob are inclinedin the direction of the front of the phonograph. The manner ofgraduating the dial is arbitrary, but I prefer to use suitable indiciato designate the off or neutral center position of the valve and tograduate the scale to indicate the extent to which the valve has beenopened in either direction. These graduations are also associated withsuitable designations, as shown.

The construction shown in Figs. 1 to 6 being mounted as shown in thedrawings, the operation for phonographic purposes, is performed in theusual manner. To modulate the volume, it is merely necessary to rotatethe knob 46, so that pointer 50 moves along the scale divisionsappearing at the right half of Fig. 5, whereby more or less of the valve22 will be interposed across conduit 24. In any setting of the valve, itwill be seen that the rotary valve is sufficiently tight to avoidrattling or setting up vibrations of its own and, moreover, avoidstheleak or interference which may attend the use of fiat or disk orspring-actuatedvalves for this purpose. It will be noted that in allsettings, the valve provides an eifective seal with respect to the"conduit 23 leading to the radio receiver, eliminating any dissipationor rattling by sympathetic vibration in the receiver diaphragm.

o For radio operation, the valve is turned to the position shown in Fig.4, in which case, it will be noted that the vibrations originating inthe telephone diaphragm are amplified in the continuously divergingradio conduit 23, which conveys the vibrations in a regular continuoussweep into the throat of the amplifier. The valve 22 provides aneffective seal of the radio conduit with respect to the conduit 24 orthe tone arm. By the present arrangement, the eiiiciency of theamplifying horn is not cut down as it would be where even minute leakageis permitted, near the small end of the horn.

, t will be seen that by rotation of the knob 6, so that the index 50passes along the lefthalf of the scale divisions in Fig. 5, the volumeemitted by the amplifier can be delicately adjusted or controlled asdesired, it being notedthat for each setting of the valve, the tightnessof the closure with respect to the tone arm is maintained. Thus, thevolume of sound is regulated without the need for adjusting theelectrical or magnetic controls ofthe receiving set in any way.

My apparatus prov-ides a compact unit which can be easily applied to aphonograph of otherwise ordinary design by merely providinga-rectangular opening asin Fig. 1, instead of the usual" circularopening. Hereinafter, I have described, however, an embodiment of theinvention applicable without any change whatsoever, to phonographs ofconstruction now in use, in which the motorboard has a circular openingonly for the mouth of the tone arm,

l\ly radio conduit and reeeiverbeing rigidly mounted; upon thephonograph independcntl y of the moving tone arm, not only dispenseswith the need for substituting the telephone: receiver for the sound boxand vice versa, with corresponding inconvenience, wear and rattle, butno added weight or drag is imposed" on the tone arm, which would belikely to unduly wear out the grooves. By myinvention, even it atelephone receiver of considerable weight is used, the operation of thephonograph is notimpaired and the life of the record is not shortened ascompared toits use on an ordinary phonograph. Moreover,

I provide highly eiiicient amplification for radio purposes in that Iavold the leak near' the throat of the amplifier which may occurparticularly at the swivel mount of the tone arm, where suchtone arnrserves to convey the vibrations from the telephone receiver to theamplifier throat, or at the radio inlet to the amplifier, where theradio receiver delivers past a flap valve in the lateral wall oftheamplifier-and near-the throat thereof.

In certain oittheclaims I have defined the especially applicable tophonographs already in use, the motorboa -d of which has a circularaperture 62 for the mouth of a tone arm only. The neck of the amplifierin such machines is secured directly below opening 62 to the motorboard-61. Inv this instance, I employ acasting 63 alsopreterahly of generallyrectangular shape, but supportedupon theupper suri'aceot the motorboardinstead ott'being countersunk in an opening therein.

Casting 633 is formed with radio conduits 65 and phonograph conduit 64.of the same general shape as the conduits 23 and 24, and

communicating respectively with the tonearm 66 and alZGlQPllOHO16661V6P67. These conduits areadapted to be selectivelyplaced in communication with. the amplifier 60. byturning a controlvalve 68 similar to the valve 21 and similarly controlled by anexteriorknob 69 connected to thestem 70 of thevalve.

The appearance of the selector unit maybe ing end of the arm isshortened to compen-- sate for the height of the casting 63 above themotorboard.

It will be understood that while in many cases, it is preferred tomountthe tonearm.

at one sidcof the. valve. knob andthe radio receiver at thezopposrteside of the valve knob,

my invention is not limited: to such arrangement, but the twoCODClLHlJS' may extend at angles relative to each other. For instance,

in a phonograph of the construction in which the tone arm 1S11101111f6Clat the corner of the.

motorboard, it would be preferred to applythe valve knob at the cornerand the radio and phonograph conduits at right angles to:' each other,extending one generally alon gthe rear and the other generally along theside wall of the phonograph cabinet. It will also be understood that thephonograph and, the radioscondui-ts may extend onein a: plane lower thanthe other, both. in; the same general dire-ctionor at an angle relativeto each other, the two conduits controlled, it desired, from a singlevalve of length to extend across:

both said conduits.

Obviously, if desired, I could employ in stead of'thesingle control:valve, separate valves for the radio and phonograph con.- duits, but theformer construction; is pre- 'l erreda V In Fig. 8' is illustrated afurther modified:

form of construction entirely concealed in the phonograph. In thisinstance, the motorboard -is formed with an opening 81: encircled by asocket member 82 which provides the usual swiveledmount for a tone arm83,

the arrangement of the tone arm above the opening beingentirely-conventional. A substantially globular valve casing 84 isscrewed or otherwise secured to the underface of the motorboard andformed with. openings 8586 registering respectively with the opening 8-1and with the neck 87 of the amplifier, the throat of the lattersecuredto the lower end of casing 84. Valve-casing- 84. is also formed withlateral opening88- registering with the enlarged end of a radio conduitS9 in a. casting 90 secured thereagainst by afiange 9a and-secured totheunderface-ot the motorboard.

a telephone receiver 91:. Gonduitx89 may be of the same general sh'apeasthe conduits-65 The conduit 89 serves to place thevalve casing incommumcataon-with' way 97 disposed at right angles to the passage-way 96cooperates with this passageway to establish communication betweenconduit 89 and the amplifier 87 when the valve is turned at right anglesto the position shown in Fig. 8. The operating means itor this valve isindicated merely in dotted lines as comprising a stem 98 and knob 99.For convenient operation of the valve, it is desirable that the stem 98be extended through a side wall of the machine and operated from theexterior of themachine by the knob. The receiver 91 instead of beingconcealed within the motor casing of the machine may be connected to theconduit 89 through the motorboard, as indicated in dotted lines in thisfigure.

.While I have shown the invention applied in a construction embodyingbuttwo conduits leading to the amplifier throat, one from the phonographrepro ducer and the other from the telephone reproducer, it will beunderstood that the invention could be carried forward to embody threeor more conduits embodying a plurality of radio conduits, or a pluralityof phonograph conduits. "Iclaim:

1. In apparatus of the character described,

'in combination, a phonograph amplifier having a throat, a tonearm forcommunication with said throat, a fixed conduit of generally rams-hornshape having its wider end delivering into said throat and adapted formounting a telephone receiver at its restricted end, said conduit havingsubstantially Y extending lengthwise thereof to block communication withthe tone arm. I

2. The combination of a tone arm and a fixed amplifier ofa pair of fixedconduits, one

of which is adapted to connect the tone arm and amplifier and the otherof which is adapted to connect a telephone receiver and the amplifier,and a common control means for optionally placing either one of saidconduits out of communication with the amplifier.

3, The combination which includes a tone arm and an amplifier, of amember formed with a plurality of passage-ways therein, one of which isadapted to connect the tone arm and the amplifier and the other ofwhich'is adapted to connect the amplifier with a telephone receiver,said last-mentioned passageway being of generally ra-ms-horn shape andcontrol means for optionally placing either of said passage ways incommunication with the amplifier.

41:. The combination which includes a casing, a .tone arm and anamplifier, of a unit mounted on top of the casing and formed with a pairof passage-ways therein, one of which is adapted to connect the tone armand the amplifier and the other of which is adapted to connect atelephone receiver with the amplifier, said last mentioned passage-waybeing relatively long and of continuously increasing diameter toward itsdelivery end, and av common control means for optionally placingeitherof said passage-ways in communication with the amplifier.

5. The combination set forth in claim 4 in which the control means whenset for telephone operation, establishes a relatively sound-tightconnection from the telephone passage-way to the amplifier. 6. Thecombination which includes a casing, atone arm and an'amplifier, of afixed unit mounted at the exterior of the casing and formed with a pairof passage-ways therein, one of which is adapted to connect the tone armand the amplifier and the other of which is adapted to connect atelephone receiver and the amplifier, and a valve manually operable toplace either of said passage-ways in communication with the amplifier,said valve in either setting afiording an entrance to the throat of theamplifier of thefull area of said throat.

7.-,The combination which includes a cabinet,a tone 'arm and anamplifier of a removablefixedunit mounted at the exterior of thecabinet, formed with a pair of passage-ways therein, one of which isadapted to connect the tone arm and the amplifier, and the other o1which is adapted to connect a telephone receiver and the amplifier, saidlast mentioned passage-way being relatively long and of continuouslyincreasing diameter toward its delivery end and a valve manuallyoperable toplace either of said passage-ways in communication with theamplifier.

8. The combination which includes a tone arm and an amplifier, amotorboard therebetween, of a removable unit fixed upon the top of saidmotor-board, formed with a pair of passageways therein, one of which isadapted to connect the tone arm and the amplifier and the other of whichis adapted to connect a telephone receiver with the amplifier, and acylindrical valvemanually operable to throttle the passage from the tonearm to the amplifier, for varying the volume, and in one position to cutoff communication between the tone arm and the amplifier for operationof the telephone.

9. The combination which includes a motor-board, an amplifier therein,of a fixed unit tac-hable to the cabinet and formed with a pair ofpassage-ways therein, both having inlets above the cabinet, one of whichis adapted to connect the tone arm and the amplifier and the other. ofwhich is adapted to connect a telephone receiver and the amplifier, saidpassage-ways uniting in a valve chamber in advance of-theircommunication with the amplifier, and a common control valve in saidchamber.

11. The combination which includes a cabinet having a motorboard, anamplifier ther in, of a unit attachable on top of said motorbcard andformed with a pair of passageways therein, one of which is adapted toconnect a tone arm and tl e amplifier, and the other of which is adaptedto connect a telephone receiver to the amplifier, and a rotatablecontrolinie-mber for optionally placing either of said passages inpartially throttled or completely open communication with the amplifier.

12. The combination which includes a cabinet and an amplifier therein,of a unit attachable thereto and formed with a pair of passage-waystherein, one of which is adapted toconnect the tone arm and theamplifier and the other of which is adapted to connect a telephonereceiver and the amplifier, a rotatable control member for variablythrottled or completely open communication between the unit andtheamplifier, a knob on the exterior of said unit for rotating said member,and indicating means associatedwith the knob, comprising .a fingercarried by the knob anda fixed dial coac ting with the finger.

13. An article of manufacture comprising acasting having a pair ofpassage-ways therein leading from one face thereof and merging at theopposite side to connect at said merging part into the amplifier of aphonograph for operative relation of a tone varm'anda telephone receivermounted at the nonmerging ends of the respective passage- .Ways, and acontrol valve member by which the cross-sectional area of thephonographpassage-way may be varied, said valve in one posltion closing thepassage-way to the tone arm and establishing communication from thetelephone receiver to the amplifier.

14. An article of manufacture comprising a casting having a pair ofpassage-ways therein adapted to connect the small end of the amplifierof a phonograph in operative relation with a tone arm and with atelephone receiver respectively, and .a common control member foroptionally connecting either passage to deliver into the small end. ofthe amplifier, said control member comprising a valve having limitedrotary movement in the casting and constructed and arranged in mannersuch that when the tone arm is in communication with the amplifier, thetone receiver is sealed therefrom and vice versa.

15. In a phonograph construction, in combination, a structure having apair of passage-ways therein, for connection to the small end of theamplifier, a telephone re ceiver at the inletend of one of saidpassageways, and a swivel structure carried by the inlet of the othersaid passage-Way to mount a tone arm, said inlets both at the upper faceof said structure.

16. In a phonograph construction, in combination, a structure having apair of passage-ways therein, for connection to :the throat of theamplifier, means at the end of one passage-way providing a swiveledmount for a tone arm carried by said structure,

and means at the end of the other passage-v way providing a mount'for atelephone receiver, said telephone receiver mount at'the upper face ofthe structure.

17. In an apparatus of the character described, in combination, anamplifier, having a throat, a sound reproducer, a conduit conneeted tosaid sound reproducer, said conduit including a cylindrical valve withan open bottom communicating with said throat and having an opening inone side thereof adapted to establish communication between said soundreproducer and said amplifier throat.

18. In apparatus of the character described, in combination, anamplifier, a plurality of sound reproducers, separate conduitsconnecting each of said sound reproducers with the small end of saidamplifier,

casing communicating with the amplifier, a

rotary valve therein to-communicate with either of said passages, andmeans limiting the rotation of said valve. through an anglesubstantially equal tosaid obtuse angle, so that in all positions ofsaid valve, communication between the two conduits is prevented.

20. .Thecombinationwith a phonograph. including a'motorboard'having anopening therein'and an amplifier registering with and directly connectedto the underface of the motorboard about said opening, of a separablestructure supported upon the motorboard, and including a tone arm and atele phone receiver, said structure having a pair of passage-waystherein, connected respectively with the tone arm and thereceiver, andboth communicating with the amplifier, and a common control member forboth passageways mounted in the structure directly above the opening inthe motorboard.

21. In combination, a cabinet, a fixed amplifying horn therein, aphonograph tone arm, a telephonic speaker above the cabinet and havingfixed position relative to the horn, and means interposed between saidphonograph tone arm and said horn on the one hand and between saidtelephonic speaker and said horn on the other hand, for selectivelyconnecting either the tone arm or the telephonic speaker to deliver intothe small end of said amplifying horn.

22. In combination, a motorboard, an amplifying horn, a phonograph tonearm, a telephonic speaker and stationary means on top of the motorboardand interposed between said tone arm and amplifying horn on the one handand between said telephonic speaker and amplifying horn on the otherhand for selectively connecting either the one or the other to deliverinto the small end of said amplifying horn a wave front of the area ofsaid small end. v

23. In combination, a motorboard, an amplifying horn, a phonograph tonearm, a telephonic speaker, and means fixed on top of the motorboard andinterposed between said tone arm and motorboard on the one hand andbetween said telephonic speaker and motorboard on the other hand forselectively connecting either the one or the other with said horn.

24. In combination, a motorboard, an amplifying horn, a phonograph tonearm, a telephonic speaker and a unit on top of said motorboard andfixedly interposed between said tone arm and amplifying horn on the onehand and between said telephonic speaker and amplifying horn on theother hand, said stationary unit being provided with means forselectively placing into acoustic communication either the tone arm orthe telephonic speaker to deliver into the small end of said amplifyinghorn.

In combination, an amplifying horn, a phonograph tone arm, a telephonicacoustic passage, and means interposed between said amplifying horn andsaid tone arm and passage, wherehy the extent of acoustic communicationbetween either the tone arm or the passage may be varied whilecommunication between the tone arm and the acoustic passage is at alltimes closed.

26. In combination, a stationary amplifying horn, a motorboard, aphonograph tone arm, a telephonic speaker, and means fixedly mounted ontop of the motorboard and carrying said tone arm and said speaker forselectively connecting either the one or the other with said horn.

Signed at New York city in the county of New York and State of New Yorkthis 17th day of May, A. D. 1924.

MAXIMILIAN IVEIL.

